This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We would like to measure the thickness and viscosity of mucus on the skin of Xenopus embryos by watching the diffusion of fluorescent dextrans using RICS and FCS. We want to know how the mucus interacts with the motile cilia. We also want to know how the mucus is affected by pH. This is important for diseases like cystic fibrosis.